Radio receiving set



Patented May 22, 1928.

PATENT @EF1-.CE1

Assrfenoits To enaivnfronn RADIO coRPo'nATroN, 'or 'crNcrNNATL'joHro'g' A con@y RADIO RECEIVING SET.

Application led April 4, 1925. Serial No. 20,849.

This invention has for its primary object and purpose, the elimination of static and other undesirable noises, in radio receiving sets.

Another object of this invention is to provide a radio receiving set that will produce sound and tone quality of maximum refined clarity, distinctiveness, and volume, from the incoming signals.

It has been the common practice, heretofore, to wire a radio receiving set or system with copper wire throughout within the entire hookup, but it has been found that copper wire does not afford a requisite shielding effect to the audio frequency currents.

Hence it is evident that copper wire is not the proper or best material to use, since it offers low impedance to both audio and radio frequencies. This is further evidentv from the fact that copper wire offers a very low resistance or impedance to the flow of electrical current of any character.

It has been found, through experience, that a. wire such, for instance, as that known as piano wire produces far better results owing to the fact that it is 99% pure steel, and more susceptible to magnetic influence than other conductors.

Piano wire also has the advantage that it is about ten times more rigid than copper wire, and in consequence a much lighter wire can be used. y

The invention is illustrated in the accompanying drawing.

The figure illustrates a typical circuit comliination showing the application of our invention.

In the drawing, et designates an aerial or other radio receptorconnected to the primary 5 of a coupling coil by the ferrous metal conductor 6. The other terminal of primary 5 is connected to a variable condenser 8 through the ferrous metal conductor 7, and the variable condenser 8 is connected to `round through the copper conductor 29. One terminal of the secondary of the coupling coil is joined to the grid by means of ferrous metal conductor 9, and the other side is connected to the positive side of the A battery, through a ferrous metal conductor 10. The filaments of the tubes 11, 12, 13 and 14 are connected in the usual manner to the A battery, through variable resistances 15. 16, 17 and 18, by means of copper conductors 19, 20, and copper conductors 28, 27, 26, 25, 24, 23, 22 and 21. The copper conductors connecting the filaments of the tubes to the A battery through the respective variable resistances, and the copper conductor 29 connecting the variable condenser 8 to ground, are the only copper conductors used, the remaining conductors in the plate and grid circuits of the respective tubes 11, 12, 13 and 14 are of ferrous metal. The B battery is connected in the usual manner, but by means of ferrous metal conductors.

From the foregoing, the following conclusion is readily drawn: Copper wire offersy low impedance to any character of current, and furthermore, offers no shielding effect. Consequently, its use in the audio frequency circuits of radio hook-ups, results in distortion of signals and interference between adjacent conductors. Steel wires, however, much smaller in diameter, have a shielding efiect tending to prevent distortion of signals and interference between adjacent conductors resulting in greater volume and clarity, and tone production true to register and free from distortion.

The chief reason for the use of piano Wire is that it is nearly 100% vpure steel,

and therefore highly magnetic.

It will be understood that our invention can be used in connection with any kind or form of radio set or equivalent device.

lV hat we claim as our invention and desire to secure by Letters Patent is 1. In a yradio receiving system, filament, grid and. plate circuits, including electric elements, means operatively connecting the elements of said grid and plate circuits` said means including leads of ferrous metal extending from element to element.

2. In a radio receiving system, filament, grid and plate circuits, including electric elements, means operatively connectingthe elements of said grid and plate circuits, said means including conductors of hard 'drawn steel extending from element to element.

3. In a radio receiving system, comprising filament, grid and plate circuits, electric elements in said grid and plate circuits, and steel Wires forming part of the last mentioned circuits, each of said Wires leading from one to another of said elements.

4: In a radio receiving system, a signal collector circuit having electric elements, a signal translating circuit having electric elements, means inter-connecting said elements,

said means including conductors of ferrous metal extending from element to element.

In testimony whereof7 We affix our signatures at Cincinnati, Ohio, this lst day 01 April, 1925.

ANTHONY BOEDEKER. JESSE s. WENTWORTH. 

